1. Field of the Disclosure
The present application relates to a liquid crystal display device.
2. Description of the Related Art
With the development of an information society, the requirements for display devices used to display images have been increased in a variety of manners. As such, flat display devices being thinner and lighter weight compared to cathode ray tubes (CRTs) of the related art are being actively researched and manufactured. The flat display devices include liquid crystal display (LCD) devices, plasma display devices (PDPs), organic light emitting display (OLED) devices and so on. Among the flat display devices, the LCD devices are now widely being used because of features such as small size, light weight, slimness and low power drive.
FIG. 1 is a disassembled perspective view showing an LCD device according to the related art.
Referring to FIG. 1, the related art LCD device includes a LCD panel 10 configured to display images, and a backlight unit 20 disposed under the LCD panel 10 and configured to apply light to the LCD panel 10. Also, the LCD device further includes a top cover 1 configured to encompass edges of the upper surface of the LCD panel 10 and combined with the backlight unit 20, and a support main 18 configured to support edges of the lower surface of the LCD panel 10 and combined with the backlight unit 20.
A gate printed-circuit-board (PCB) 13 is disposed beside an edge of the LCD panel 10 and configured to apply gate signals to gate lines of the LCD panel 10. A data PCB 15 is disposed beside another edge of the LCD panel 10 and configured to apply data voltages to data lines of the LCD panel 10. A plurality of flexible printed-circuit substrates 17 are arranged between the gate and data PCBs 13 and 15 and the LCD panel 10. As such, the gate PCB 13 can be connected to the gate lines of the LCD panel 10 through the flexible printed-circuit substrates 17. Similarly, the data PCB 15 can be connected to the data lines of the LCD panel 10 through the flexible printed-circuit substrates 17.
The backlight unit 20 includes a box-shaped bottom cover 70 with an opened upper surface, light source 50 disposed in an inner side surface of the bottom cover 70, a light guide plate 40 disposed parallel to the light source 50, optical sheets 30 disposed on the light guide plate 40, and a reflection sheet 60 disposed under the light guide plate 40. The light guide plate 40 is configured to convert incident light from the light source 50 into a two-dimensional light. The optical sheets 30 are configured to diffuse and converge the two-dimensional light entered from the light guide plate 40. The reflection sheet 60 reflects light progressing downward from the light guide plate 40 toward the LCD panel 10, in order to reduce light leakage.
The backlight unit 20 further includes a housing 51 configured to encompass a side of the light source 50. The housing 51 guides light emitted from the light source 50 to enter an incident surface of the light guide plate 40.
In general, light emitting diode (LED) can be used as a light source for the LCD device. In detail, an LED configured to emit visible light is used as a light source for the LCD device.
Such an LCD device can be used for a special purpose. In other words, the LCD device can be used when concealment is required in nighttime under a special circumstance such as a military operation and so. However, it is difficult to use the LCD device under the circumstance in which concealment is required because a user using the LCD device is exposed to everyone. This results from the fact that a visible LED is employed as a light source of the LCD device. Meanwhile, night vision goggles using infrared light instead of visible light are being mainly employed, in order to secure the view in the nighttime.
In view of this point, it is necessary to develop an LCD device for special purposes which uses both visible light and infrared light.